1. Field of the Invention
This invention relates to melt processable copolymer of etherimideimide/etherimide herein-after identified as PEII/PEI copolymer and the preparing method thereof, particularly preparing a copolymer having superior meltviscosity to polyetherimideimide of U.S. Pat. No. 5,212,277 by copolymerizing with a polyetherimide. Having a imideimide moiety, polyetherimideimide resin shows good heat resistance but due to its high melt viscosity should be treated melting wrought around at high temperature of 380.degree. C.
But this melting wrought cause so much pyrolysis that special processing system is needed. In this respect polyetherimideimide resin have a weak point of high cost for its equipment.
Accordingly, the present inventors have conducted long term investigations and studies in order to prepare a etherimideimide/etherimide copolymer which have not only the characteristics of polyetherimideimide resin in prior arts but also highly improved meltviscosity and at last succeed to prepare a copolymer which have not only a preferable solubility and other physical properties but also good processability by improving the copolymerization process and copolymerizing with a polyetherimide.
The objection of this invention is preparing PEII/PEI copolymer of following formula (I). ##STR4## wherein, R and R' are independently selected from the groups of ##STR5## Ar and Ar' are independently selected from the following groups ##STR6## (wherein, R1 is H or C1-C6 alkyl group,
R2 is II or C1-C4 alkyl group, and PA2 R3 is --O--, --CO--, --SO--, --SO2--.); and
n and m are independently an integer between 5 and 500.
2. Description of the Related Art
Generally, engineering plastics have excellent thermo-mechanical properties under severe physical and chemical conditions for a long time, and thus they have been used as raw material for industrial accessories and structural housings in industrial fields such as electrics, electronics, precision instruments, etc.
Polyimide resin (hereinafter identified as PI) especially wholly aromatic PI, is one of the above engineering plastics, having excellent heat-resistance.
However, since wholly aromatic PI is very difficult to mold its molding product can be made by special molding methods such as compression or mechinary process of molding materials.
To improve the disadvantage of PI research has been made. Among them, the polyetherimide (hereinafter identified as PEI), which was first synthesized by General Electric Co. of USA in 1982, has come into the market in the trade name of ULTEM.RTM..
PEI is a special engineering plastic having properties such as good mechanical stress, flame retardent, electric, chemical resistance, processability and heat-resistance.
A range of PEI application has extended to a wide range such as a basic materials for automobile, electrics, electronics, household electrical appliances, public transport such as airplane, fiber and film etc.
These inventor have developed and manufactured novel polyetherimideimide resin (hereinafter identified as PEII) as shown by U.S. Pat. No. 5,212,277.
PEII has additional imide group as compared to PEI which already consisting of phthalimide group and ether group.
PEII can be produced either melt or solution polymerization process and it exhibits equal or even superior thermal stability and mechanical properties to PEI.
Heat deflection temperature (hereinafter identified as HDT) of PEII is improved over 20.degree. C. because glass transition temperature (hereinafter identified as Tg) has improved as compared with PEI.
Although Tg and HDT of PEII have remarkably improved than PEI, mechanical properties such as tensile strength have not improved significantly because the bulkiness of diamine interferes with the formation of higher molecular weight polymer.
Additionally, by the bond effect of imide-imide in the PEII, tensile strength is increased and cause high melt viscosity. As a result of continuous research, inventors succeed to invent copolymer having better thermal stability than PEI and lower melt viscosity than PEII, which is excellently improved in its processability.